The only thing I think is different, is the magwell in the front is "flat" and cut in a little deeper to expose the bottom "lip" were as a ar15 lower kind of bulges out. And of course the 2 "holes" by where the stock goes in(I have no clue what these are still)

The upper IMO is the only thing that's visibly different.

So in other words yes, I think you should be able to easily make on out of a ar15 lower.

I believe the H&K magwell is longer/straighter across the bottom/less angled. Some of the plastic magazines won't fit it without being modified. P-mags are a no-go, but I think there is a newer version that does fit the H&K lower receiver.

I quess I'm blind unless I put them side by side. The 416 looks dang near exactly the same as an AR15. I assumed it was just like everyone elses version of the AR. Just enough tiny differences to claim that theirs is better, but milspec everywhere it counted.

Enforcement, NOT Amnesty!!!!!!

"If they’re going to come here illegally, apply for & receive assistance through a corrupted Government agency encouraging this lawless behavior, work under the table & send billions of dollars each year back to their families in Mexico, while bleeding local economies dry, protest in our streets waving their Mexican flags DEMANDING rights, while I have to press ’1′ for English, then they need to be shipped back to where they came from!" -Chad Miller